基于黄土高原生态屏障区土壤退化治理需求，研究黄土高原典型草本植物对纳米二氧化硅的响应机制，为纳米二氧化硅应用于黄土高原土壤修复提供理论依据，试验以典型草本植物紫花苜蓿和高羊茅为研究对象，通过梯度浓度纳米二氧化硅添加试验[0(CK)、0.2%、0.8%、2.0%]，系统揭示纳米材料对植物根系形态发育及生物量的调控作用，采用根系形态解析与熵权综合评价方法，量化不同处理下根系参数的响应。结果显示，0.8%纳米二氧化硅浓度处理对两物种均产生显著促生效应，苜蓿总根长和根体积较不添加纳米二氧化硅处理提升61.5%、26.7%，高羊茅根系数量、根系体积增幅达113.9%、86.6%；而2.0%浓度处理引发显著抑制作用，两物种根系形态指标及生物量均发生不同程度的降低。高羊茅表现出更强的浓度敏感性，0.8%处理下其根体积增益较紫花苜蓿高60个百分点，但在2.0%处理时鲜重降幅(27.3%)为紫花苜蓿(13.6%)的2倍，且根系直径下降28.2%，而紫花苜蓿仅下降15.9%。机制解析表明苜蓿通过侧根系统冗余化增强抗逆性，而高羊茅主根延伸易受纳米颗粒物理堵塞影响。熵权模型综合评价显示0.8%浓度处理下两物种综合得分均达理论最大值(1.00)，证实该浓度具有最优根系改良效益。

Based on the soil remediation needs in the ecological barrier zone of the Loess Plateau, this study investigated the response mechanism of selected typical herbaceous plants to nano-SiO₂, providing a theoretical basis for the application of nano-SiO₂ in soil restoration in the Loess Plateau. Two typical herbaceous plants-alfalfa (Medicago sativa) and tall fescue (Festuca arundinacea)-were used as research subjects, a gradient addition experiment with nano-SiO₂ concentrations of 0 (CK), 0.2%, 0.8%, and 2.0% was conducted to systematically reveal the regulatory effects of nanomaterials on root morphological development and biomass. Root morphological analysis and entropy-weighted comprehensive evaluation were employed to quantify responses of root parameters under different treatments. Results showed that the 0.8% concentration significantly enhanced growth in both species. Alfalfa exhibited 61.5% and 26.7% increases in total root length and root volume versus the control, while tall fescue showed 113.9% and 86.6% gains in root number and volume. Conversely, the 2% treatment caused significant inhibition, reducing root morphological indices and biomass across both species. Tall fescue demonstrated greater sensitivity to concentration changes, its root volume gain at 0.8% treatment exceeded alfalfa's by 60 percentage points, but its fresh weight reduction at 2% treatment (27.3%) was twice that of alfalfa (13.6%), and root diameter decreased by 28.2% in tall fescue, versus a milder reduction of 15.9% in alfalfa. Mechanistic analysis revealed alfalfa's enhanced stress resistance through lateral root redundancy, while tall fescue's primary root elongation was more susceptible to physical blockage by nanoparticles. The entropy-weighted model confirmed that both species achieved theoretical maximum comprehensive scores(1.00) under 0.8% treatment, validating that this concentration offers the optimal root improvement benefit.

S154.2

甘肃省科技计划自然科学基金项目(25JRRA75)；兰州资源环境职业技术大学校级科研项目(X2024A-06)；甘肃省高校教师创新基金项目(2025A-298)。